Enhancing Papaya Shelf-Life With Upcycled Pea Starch–Neem Oil Polymeric Nanoparticles Synthesized via a Novel Rapid Spray Nanoprecipitation Technique

Marketing of fresh ripened papaya is challenging due to its short shelf-life (2–3 days) resulting in high post-harvest losses (30%–50%), primarily caused by fungal diseases such as Anthracnose. Neem oil (NO) is well recognized for its ability to extend the shelf-life of fresh produce, but encapsulation is required to preserve its properties. This study aimed to stabilize and encapsulate NO in a polymeric material via a novel rapid spray nanoprecipitation technique to extend the shelf-life of papaya fruits under cold storage (4°C ± 1°C, 80% ± 2% RH) and room temperature (22°C ± 2°C, 45% ± 5% RH). The shelf-life of papayas was extended by 10 days compared to the control when the nanoparticle coating was combined with cold storage showing no fungal growth. After 10 days of storage, weight loss in coated fruits was approximately ~6.22% at cold storage temperatures and 17.5% at room temperature, whereas, in the control group, the weight loss observed was 9.09% at cold storage temperature and 27.46% at room temperature. Additionally, the NO infused starch nanoparticle coating significantly (p < 0.05) maintained fruit firmness compared to untreated control samples. The NO inhibited fungal growth, while the starch polymer coating slowed ripening. Hence, the application of nanoparticle coating in this study can act as an active agent for prolonging the shelf-life of papayas within the food distribution chain.